Oil burner control



E. H. WHITE April 13; 1937.

OIL BURNER CONTROL Filed Sept. 21, 1935 3 Sheets-Sheet 1 Inventor: E. H. White.

April 13, 1937. v E TE 2,077,294

OIL BURNER CONTROL Filed Sept. 21, 1953 3 Sheets-Sheet 2 IIS m mu

1/ Fig-5v 11s use Inventor:

I27. E. H. WhrL'ev I68 Bg 25 H:

April 13, 1937. E. H. WHITE I 2,077,294

OIL BURNER CONTROL Filed Sept. 21, 1933 's Sheets-Sheet 3 A a I I05 13 lm Kl'tor-neg.

Patented Apr. 13, 1937 UNITED STATES PATENT OFFICE 3 Claims.

' The present invention has relation to an oil burner control.

An object of the invention is to provide an oil burner control wherein will be incorporated various improved features and characteristics of construction novel both as individual entities of said oil burner control and in combination.

A further object is to provide an oil burner control which, in its entirety, except for the room thermostat, or equivalent, the ignition device, motor, and valve for said control, and certain electrical wiring, which parts must of necessity be elsewhere, may be housed as a single unit capable of easy and practicable removable assembly with the stack of an oil burner furnace.

A further object is to provide in the oil burner control, a stack thermostat of novel and improved construction adapted to manipulate various electric switches of said control in novel and im- 2 o proved manner.

A further object is to provide in the oil burner control, a room thermostat, or equivalent, including a permanent magnet the functions of which are to firmly hold said contact elements 25 in engagement when once together and thus provide a regulatable differential for the smooth and proper operation of the oil burner control, and to provide a quick and snappy make and break of the switch of said room thermostat.

39 And a still further object is to provide an oil burner control wherein the ignition device, the motor, and the valve when employed, are adapted to be connected in line wire circuits of relatively high voltage, while all of the other electricity 3 5 conveying parts of said control, including the switches manipulated by the stack thermostat, are adapted to be connected in circuits of relatively low voltage including the stepped-down secondary of a transformer associated with said 40 line wires.

With the above objects in view, as well as others which will appear as the specification proceeds, the invention comprises the construction, arrangement and combination of parts as now to be 45 fully described and as hereinafter to be specifically claimed, it being understood that the disclosure herein is merely illustrative and intended in no way in a limiting sense, changes in details of construction and arrangement of parts being 50 permissible so long as within the spirit of the invention and the scope of the claims which follow.

In the accompanying drawings forming a part of this specification,

Fig. 1 is a vertical sectional view of an oil burner 55 control made according to the principles of the invention, disclosing said oil burner control as when applied to use, the section being taken on line l--| in Fig. 3;

Fig. 2 is a detail sectional view of the stack thermostat of the oil burner control, taken as on line 22 in Fig. 1;

Fig. 3 is an elevational view of the oil burner control with cover removed, as seen from the right in Fig. 1;

Fig. 4 is a vertical sectional view taken as on line 4-4 in Fig. 5;

Fig. 5 is a vertical sectional view taken on line 5-5 in Fig. 3;

Fig. 6 is a vertical sectional View taken as on line 6-6 in Fig. 5;

Fig. 7 is a detail sectional view taken as on line 'l----! in Fig. 4;

Fig. 8 is a horizontal sectional view taken on line 8-8 in Fig. 3;

Fig. 9 is a detail sectional view taken on line 9--9 in Fig. 3; and

Fig. 10 is a diagrammatic view disclosing the wiring system of the oil burner control.

With respect to Fig. 10 of the drawings and the numerals of reference thereon, [5 represents the ignition device, I6 the motor, and I! the solenoid for actuating the control valve of an oil burner. The major portion of the improved control for said oil burner, indicated generally at i8, is shown applied to the stack IQ of an ordinary or preferred type of oil burner furnace (not shown). See Fig. 1 in connection with Fig. 10.

Any ordinary thermostatic element 20, in remote relation to the oil burner furnace, as, for instance, in a room to be heated, constitutes means for actuating an electric switch 2|, as disclosed a thermal electric switch, for the ignition device H3. The electric switch 2|, actuated by the thermostatic element 20, cooperates with said thermostatic element to control circuits, in a manner to be set forth, including said electric switch 2| and a second electric switch 22, as disclosed also a thermal electric switch, for the motor l6 and the control valve ll. The electric switches 2i and 22 are electrically connected and said electric switch 22 itself cooperates with the thermostatic element 20, in a manner also to be set forth, to control a circuit through said electric switch 22. See Figs. 4, 5 and 10.

The oil burner control also includes a stack thermostat 23 which manipulates, in a manner to be made clear, additional electric switches in the circuits having the thermal electric switches 2| and 22, and said oil burner control desirably also includes a safety electric switch 24 which is connected in series with said switches 2| and 22 and is associated with the thermal electnc 5 switch 2| in a novel and improved manner to be set forth.

The stack thermostat 23 is mounted directly in the furnace stack l9, and the thermal switches 2| and 22, safety switch 24, and additional switches of the oil burner control in the circuits having said switches 2|, 22 and 24 are mounted in a casing 25 adjacent said stack |9 at the outside thereof, as shown more clearly in Fig. 1. As disclosed, the stack l9 includes an opening 26, and a bracket 21 is permanently attached to said stack, as at 28, about said opening, the bracket having a desirably horizontally disposed hollow neck 29 which extends outwardly from the stack. A hollow standard or carrying memher 39, slidably received in the neck 29, rigidly supports, as at 3|, the legs of a Ubracket 32, and rigidly supports, as at 33, an insulating panel 34, which may desirably be composed of asbestos, or other suitable material. The Ubracket 32 in turn supports a stack thermostatic element 35, and the panel 34 in turn supports the casing 25. The supporting or carrying member may include air openings as shown.

The thermostatic element 35 is of the peculiar 30 construction as best shown in Figs. 1 and 2, including a plurality of reversely positioned U- members 36 adjacent legs of which are welded or otherwise secured together as at 31. Each U-member 36 is a bi-metallic strip, and a leg of 3 an outermost U-member, at the left in Fig. l, is attached, as at 36, to the base 39 of the Ubracket 32. A leg of the opposite outermost U-member 36, at the right in said Fig. 1, is attached, as at 40, to a rod 4|, which may desirably be square in 40 cross-section. The arrangement is such that the rod 4| extends horizontally out of the stack and into the casing 25, and said rod may have free sliding fit in circular openings, designated 42 and 43, in the base 44 of the. standard or member 39 45 and in the panel 34, respectively. The arrangement as disclosed is such that when the thermostatic element 35 is heated, the legs of each U- member 36 thereof move toward each other, to cause the rod 4| to move inwardly of the stack and inwardly of the casing 25, and when said element 35 is cooled, said legs of each U-member move apart, to cause said rod 4| to move outwardly of said stack and outwardly of said casing, as will be understood.

As is evident, the unit including the member 30, the stack thermostat, the panel 34, the casing 25, etc., is very easily and conveniently insertable in and removable from the stack through the hollow neck 29. As illustrated in Fig. 1, the standard or carrying member 30 may have its position fixed when inserted into the stack by means of a set screw 45.

The casing 25 is supported upon the panel 34, in spaced relation thereto, by headed and nutted bolts 46 which pass through said panel and the base 41 of said casing and through spacing blocks or members 48 therebetween.

A transformer 49, for a purpose to be set forth, is suitably carried by the casing 25, and said base 41 of said casing convenientlysupports an insulating panel 59, which may desirably consist of bakelite, or other suitable material. As illustrated, the panel 50 is supported upon the base 41 of the casing, in spaced relation thereto, by

headed and nutted bolts 5| which pass through said panel 50 and base 41 and through spacing blocks or members 52 therebetween.

The panel 59 also includes a circular opening, designated 53, in which the rod 4| freely slides, said rod having its end opposite the thermostatic element 35 terminating adjacent the cover 54 of the casing 25. Said cover 54 is removably attached to the casing, as by screws 55.

It will be seen that the circular openings 42, 43 and 53, or any one of said openings, provide a four point, or two point, bearing for the squared rod 4|. Also, it is evident that said rod does not turn as it is moved longitudinally or inwardly and outwardly by the thermostatic element 35, but always moves horiontally without any tendency toward transverse rocking. Friction upon the rod is thus kept at a minimum at location or locations where said rod is slidably mounted. And furthermore, it will be seen, the thermostatic element 35, while contracting with heat to have tendency to keep out soot, is wide open to passage of gases through it, and heat changes work said thermostatic element to cause it to have tendency to remove soot, etc., especially when the U-members 36 are disposed so that the widths of the legs thereof are vertical.

The outer portion of the rod 4| is desirably I-shape in cross-section, including an upper horizontal portion 56 and a lower horizontal portion 51. The portion 56 slidably carries a U-clip 58, and the portion 51 slidably carries a U-clip 59. Flanges 60 on said U-clips 58 and 59 retain the U-clips upon the portions 56 and 51, and a small fiat spring 6| between each U-clip and its corresponding portion 56 or 51, as the case may be, frictionally retains each said Uclip against tendency toward sliding movement upon the rod 4|. See Figs. 1, 3, 4, 8, 9 and 10.

The insulating panel 50 rigidly supports, as at 62, a conducting plate 63, and said plate 63 conductively carries, as at 64 and 65, respectively, a pair of movable switch elements denoted 66 and 61. Said movable switch elements 66 and 61 are adapted to engage stationary switch elements designated 68 and 69, respectively, insulatively mounted, as at 18 and II, upon a bracket 18 suitably attached to the panel 59. The conducting plate 63 insulatively carries, as at 12, a movable switch element 13 having a conducting boss 14 adapted to engage a conducting boss 15 upon the movable switch element 66 and to be actuated to cause said movable switch element 66 to be removed from the stationary switch element 68.

A stop member 76, insulatively mounted as at 11 upon the bracket 18 carried by the insulating panel 59 for adjustment longitudinally of the rod 4|, limits inward movement of the U-clip 56, said U-clip including an extension portion 19 adapted to engage said stop member 16. Outward movement of the U-clip 5B is limited by engagement of said extension portion 19 with the movable switch element 61 when itself engaged with the stationary switch element 69. It should be remarked that the movable switch element 61 is of resilient structure and removes itself from the stationary switch element 69 except when said switch elements are held in engagement by the extension portion 19 of the U-clip 58. See Figs. 1, 9 and 10. A stop member 80, insulatively mounted as at 8| upon the bracket 18 for adjustment longitudinally of the rod 4|, limits outward movement of the U-clip 59, said Uclip including an extension portion 82 adapted to engage said stop member 80. Inward movement of the U-clip 59 causes the extension portion 82 to engage the movable switch element 13. Said movable switch element 13 is of resilient construction and is in open position when the oil burner furnace is cold, while the switch elements 66 and 68 are, when said furnace is cold, engaged with each other, as disclosed in Figs. 8 and 10. The arrangement is such that inward travel of the U- clip 59' first causes the conductive bosses l4 and 15 upon the movable switch elements I3 and 66, respectively, to engage each other, and said movable switch element 68 to later be removed from the stationary switch element 68.

The drawings disclose the various parts of the oil burner control positioned as when the oil burner is inactive or extinguished and the space to be heated is at desired temperature. At this time, the thermostatic element 35 has its greatest expansion, assuming the stack I9 is at minimum temperature, so that the rod 4| is at the limit of its outward movement, to cause the extension 19 upon the U-clip 58 to engage the movable switch element 61 and hold it against the stationary switch element 69, and to cause the extension 82 upon the U-clip 59 to engage the stop 88. Speaking generally, when the space to be heated calls for heat, the ignition of the oil burner is effected, and immediately the stack |9 begins to warm up. This causes the thermostatic element 35 to commence to contract. Almostimmediatelythe extension 19 upon the U-clip 58 is withdrawn from the movable switch element 61 to allow said element to resiliently remove itself from the stationary switch element 69. Soon thereafter, upon further inward movement of the rod 4|, the extension I9 upon the U-clip 58 engages the stop 16 to be there arrested, before said rod 4| reaches the limit of its inward movement. After the extension 19 engages the stop 16 upon inward movement of the rod 4|, said rod slides relatively to the clip 58 during the further inward movement of the rod. When then the space to be heated ceases to call for heat and the oil burner is extinguished, as will be fully explained, the thermostatic element 35 commences to expand at the moment the stack l9 commences to cool down, and the rod 4| simultaneously commences to move outwardly, carrying with it the U-clip 58 and its extension 19. Thus it will be seen that the exact time of engagement of the switch elements 61 and 69 with each other upon the cooling down of the furnace can be nicely regulated by the original setting of the stop 16. Also, when the oil burner is ignited as before stated to warm the stack and thus cause the thermostatic element 35 to commence to contract, the extension 82 upon the U-clip 59 moves inwardly from the stop 88, and thereafter, upon further inward movement of the rod 4| said extension 82 engages the movable switch element 13 and causes the boss 14 thereon to engage the boss 15 upon the movable switch element 66. As the rod 4| then moves still further inwardly, the movable switch element 66 is removed from the stationary switch element 68, through the instrumentality of the engaging bosses I4 and 15. As before mentioned, both of said bosses are contact or conducting members. Thereafter, when the burner is extinguished, as above mentioned, and the thermostatic element expands with the cooling down of the stack to cause the rod 4| to move outwardly,

the clip 59 with extension portion 82 simultaneously moves outwardly, first allowing the movable switch element 56 to engage the stationary switch element 68 and then allowing the resilient switch element 13 to remove its boss or contact 14 from the boss or contact 15 upon the movable and resilient switch element 66. Upon further outward movement of the rod 4| with the cooling of the stack, the extension 82 engages the stop 88, before said rod 4l reaches the limit of its outward movement, and thereafter as said rod 4| moves still further outwardly, it slides relatively to the U- clip 59. When then the space to be heated later calls for heat and the oil burner is ignited to cause the stack to heat up and the thermostatic element 35 to a result commence to contract, the rod 4| simultaneously commences to move inwardly, carrying with it the U-clip 59 and its extension 82. Thus the exact time of engagement of the switch elements 13 and 66 and the disengagement of the switch elements 66 and 68 upon the heating up of the furnace can be nicely regulated by the original setting of the stop 88.

The structure of the thermal electric switch 2| for the ignition device I 5 is best disclosed in Figs. 1, 3, 4, 5, 7, 8 and 10. As there shown, a resistor 83 desirably consists of a single strand of suitable wire of relatively fine dimension having its end portions attached to terminals, designated 84 and 85, respectively, mounted upon an insulating block 88 itself conveniently carried, as by a bracket 81, upon the insulating panel 58. The intermediate portion of the wire resistor 83 extends back and forth across the outer face of an insulating block 88, desirably of lava, and outer parts of said intermediate portion of the wire strand 83, in spaced relation to the terminals 84 and 85, are rigidly attached to an outer portion of said insulating or lava block 88, while inner parts of said intermediate portion are rigidly attached to said insulating block 86, between the terminals 84 and 85. More specifically, the insulating block 86 supports a series of alining, spaced apart lugs or posts 89, and the insulating block or lava 88 supports a similar series of alining, spaced apart lugs or posts 98, about allof which lugs or posts 89 and 98 the wire strand 83 is successively wound. In the manufacture of the thermal electric switch 2|, an end of the wire strand resistor 83 thereof may be first attached to a terminal 84 or 85, an adjacent portion of said wire strand may then be wound one or more times about an outermost lug or post 89, then the next adjacent portion of the wire strand may be wound about an outermost lug or post 98, then about the lug or post 89 next adjacent one already wired, then about the lug or post 98 next adjacent one already wired, and so on, until the lugs or posts are all wired, and finally the wire strand may be attached to the terminal 85 or 84. If desired, after the lugs or posts are all wired, a touch of cement may be applied, as at 9| in Figs. 4 and 5, back of each lug or post, to insure that the wire cannot become accidentally removed from the lugs or posts. One end portion of the block or lava 88 is conveniently pivoted to the bracket 81, as by a small shaft 92 which passes through ears upon said block or lava 88 disposed between-flanges of said bracket. A coil spring 93, attached to the bracket 81 at 94 and to the inner face of the block or lava 88 at 95, urges said block or lava 88 to swing on its axis toward the insulating panel 58. Each length of the wire resistor 83 is taut or tensioned between the lugs or posts 89 and 98 to normally hold the block or lava 88, against the action of the coil spring 93, at its farthest distance from the panel 58, and so that the blocks 86 and 88 will desirably be in approximate alinement. And the wire strand resistor 83, which is obviously noninductive, is composed of material having a coefficient of expansion sufliciently great to cause immediate lengthening of said wire strand resistor to an extent to allow movable contact elements upon the block or lava 88 to make electrical engagement with stationary contact elements upon the insulating panel 50 immediately when only a very small current of electricity is applied to said resistor 83 in a manner to be explained. As disclosed, the insulating panel 50 suitably supports a stationary contact strip 96 and a stationary contact plate 91, while the block or lava 88 has a shaft 98 extending longitudinally from the free end thereof, upon which shaft 98 the intermediate portion of a double contact element 99 is rotatably mounted. Said shaft 98 carries a coil spring I00 one end IIII of which engages the contact element 99 and the other end I02 of which engages the block or lava 88 to hold a contactor I03 of said element 99 in engagement with the plate 91 and another contactor I04 of said element out of engagement with the strip 96.

.See Figs. 3, 4, 5 and 8. Evidently, when the resistor 83 becomes lengthened, the coil spring 93 acts against the tendency of the weaker coil spring I00 to cause the contactor I04 to engage the contact strip 96. Also, the insulating panel 50 suitably supports a pair of spaced apart screw contacts, denoted I05 and I06, respectively, which screw contacts extend from said panel 50 into cut-out portions I01 and I08 of the block or lava 88. Said member 88 carries spring clip contacts, denoted I09 and H0, respectively, the former being adapted to engage the contact I05 and the latter being adapted to engage the contact I06 when the resistor 83 is energized in the manner to be set forth.

The structure of the thermal electric switch 22 for the motor I6 and the control valve I1 is best disclosed in Figs. 3, 4, 8 and 10. As there shown, a resistor I I I desirably consists of a single strand of suitable wire, similar to the wire of the strand 83, having its end portions attached to terminals, designated H2 and H3, respectively, mounted upon an insulating block II4, similar to the block 86, itself conveniently carried, as by a bracket I I5, upon the insulating panel 50. The intermediate portion of the wire resistor III extends back and forth across the outer face of an insulating block II6, also desirably of lava, and outer parts of said intermediate portion of the wire strand I I I, in spaced relation to the terminals H2 and I I3, are rigidly attached to an outer portion of said insulating or lava block I I6, while inner parts of said intermediate portion are rigidly attached to said insulating block II4, between the terminals H2 and H3. More specifically, the

insulating block II4 supports a series of alining,

spaced apart lugsor posts I I1, and the insulating block or lava I I6 supports a similar series of alining, spaced apart lugs or posts II8, about all of which lugs or posts Ill and H8 the wire strand III is successively wound. In the manufacture of the thermal electric switch 22, an end of the wire strand resistor III thereof may be first attached to a terminal H2 or II3, an adjacent portion of said wire strand may then be wound one or more times about an outermost lug or post III, then the next adjacent portion of the wire strand may be wound about an outermost lug or post II8, then about the lug or post III next adjacent one already wired, then about the lug or post I I8 next adjacent one already wired, and so on until the lugs or posts are all wired, and finally the wire strand may be attached to the terminal H3 or II2. If desired, after the lugs or posts are all wired, a touch of cement may be applied, as at H9 in Fig. 4, back of each lug or post, to insure that the wire cannot become accidentally removed from the lugs or posts. One end portion of the block or lava H6 is conveniently pivoted to the bracket II5, as by a small shaft I20 which passes through ears upon said block or lava II8 disposed between flanges of said bracket. A coil spring I2I, attached to the bracket H5 and to the inner face of the block or lava I I6, urges said block or lava II6 to swing on its axis toward the insulating panel 50. Each length of the wire resistor III is taut or tensioned between the lugs or posts III and H8 to normally hold the block or lava II6, against the action of the coil spring I2I, at its farthest distance from the panel 50, and so that the blocks H4 and H8 will desirably be in approximate alinement. The wire strand resistor III may desirably be composed of the same material as is the wirestrand resistor 83 to cause immediate lengthening thereof to allow movable contact elements upon the block or lava II6 to make electrical engagement with stationary contact elements upon the insulating panel 50 immediately when a small current of electricity is applied to said resistor I I I in a manner also to be explained. As disclosed, the insulating panel 50 suitably supports a stationary contact strip I22, and the block or lava I I6 has a shaft I23 extending longitudinally from the free end thereof, upon which shaft I23 the intermediate portion of a contact element I24 is rotatably mounted. Said shaft I23 carries a coil spring I25 one end I26 of which engages the contact element I24 and the other end I21 of which engages the block or lava I I6 to hold a contactor I28 of said element I24 in engagement with the plate I22 and another contactor I29 of said element out of engagement with the plate 91. See Figs. 3, 4 and 8. Evidently, when the resistor III becomes lengthened, the coil spring I2I acts against the tendency of the weaker coil spring I25 to cause the contactor I29 to engage the contact plate 91. Also, the insulating panel 50 suitably supports a screw contact I30 which extends from said panel 50 into a cut-out portion I3I of the block or lava II6. Said member II6 carries a spring contact clip I32 which is adapted to engage the contact I30 when the resistor III is energized in the manner to be set forth.

The structure of the safety electric switch 24 and its manner of association with the thermal electric switch 2| is best disclosed in Figs. 1, 3, 5, 6, 7, 8 and 10. As there shown, I33, attached to the bracket 81 as at I34, rigidly carries one end of a bi-metallic strip I35 which is in proximate, superimposed relation to the resistor 83 to receive heat from said resistor when it is energized. The body of the bi-metallic strip I35lies adjacent an opening I36 in said bracket I33 so as to be freely movable toward and away from said resistor 83. An extension I31 of the bracket I33, at the end thereof to which the bi-metallic strip I35 is secured, rigidly supports, as at I38, one end portion of a switch carrying member I39. The opposite end portion of said switch carrying member I39 may be fixed in spaced relation to the body of the bracket I33 in any convenient manner, as by a small bolt I40 including a nut I4I thereon engaging said bracket I33 and nuts I42 on said bolt engaging opposite surfaces of said switch carrying member I39. A ledge or flange I43 upon the member I39, between said member and the bi-metallic strip I35, rigidly supa bracket ports, as at I44, a contact carrying member I45, which is desirably parallel with and in spaced relation to both the member I39 and the bi metallic strip I35. Numeral I46 designates a stationary contact element insulatively carried by the member I45. A movable and resilient contact element I 41 is insulatively attached to the ledge or flange I43 and the member I45 at I44. Numeral I48, Fig. 10, represents a terminal for the element I41. Said contact element I41 is of structure to spring away from the fixed contact element I46 except when held in engagement therewith as follows. The end of the member I45 opposite the ledge or flange I43 hingedly supports, as at I49, an L-lever I50, the axis of said lever being arranged in the shorter leg I5I thereof. The longer leg I52 of said L-lever extends to position over the movable and resilient contact element I41, and conveniently carries, as at I53, an insulating strip I 54 arranged against the inner surface of said longer leg and adapted to engage said contact element I41. The bi-metallic strip I35 includes an oblique extension I55 which normally engages the lower portion of the inner surface of the shorter leg I5I of the L-lever to hold the insulating strip I54 against the movable and resilient contact element I41 and to in turn hold said element I41 in engagement with the stationary contact element I46. The arrangement is such that when the bi-metallic strip I35 warps in direction toward the resistor 83, due to the reception of sufiicient heat by said bimetallic strip from said resistor, the oblique extension I55 is removed from the free end of the shorter leg I5I to thus allow the movable and resilient contact element I41 to spring away from the stationary contact element and cause the longer leg I52 to move outwardly and the shorter leg I5I to move inwardly. Thereafter, even when the bi-metallic strip I35 cools down, the contact elements I41 and I46 will remain separated. To again bring said contact elements I61 and 146 together, and thus re-set the safety switch, it is necessary to manually depress a push button I56, arranged in the carrying member I391, against the action of the movable and resilient contact element I41. Obviously, depression of said push button I56 swings the L-lever I50 on its axis I49, moving the longer leg I52 inwardly and the shorter leg I5I outwardly, past the oblique extension I55 to position where the inner surface of said shorter leg is again engaged by said oblique extension of the bi-metallic strip I35, as shown very clearly in Fig. 5, of course when said bi-metallic strip is sufiiciently unheated to be thus normally positioned.

The stationary contact plate 91 carries a terminal I51 receiving an incoming line wire I58. The insulating panel 50 conveniently supports, as by a metallic strip I59 thereon, a terminal I60 receiving an incoming line wire I6I.

A lead wire I62 connects the stationary contact plate 91 with one side of the primary of the transformer 49, and a lead wire I63 connects the terminal I60 with the opposite side of said primary.

A lead wire I64 connects the terminal I60 with the ignition device I5, the motor I6 and the control valve I1. A lead wire I65 connects said ignition device with a terminal I66 carried by the stationary contact strip 96. A lead wire I61 connects said motor I6with a terminal I68 carried by the stationary contact strip I22, and a lead wire I69 connects said control valve I1 with said terminal I68.

The conducting plate 63 insulatively carries a terminal I10, and conductively carries a terminal IN.

A lead Wire I12 connects one side of the secondary of the transformer 49 with the terminal I10, and a lead wire I13 connects said terminal I10 with the movable contact element 20 of the room thermostat. A lead wire I14 connects the terminal I1I with the stationary contact element I15 of said room thermostat.

A lead wire I16 connects the conducting plate 63 with the screw contact I05. A lead wire I11 connects the stationary switch element 68 with the screw contact I06. A lead wire I18 connects the stationary switch element 69 with the spring clip III]. A lead wire I19 connects the spring clip I09 with the spring clip I32. A lead wire I connects the movable switch element 13 with the screw contact I30.

A lead wire I8I connects the lead wire I18 with the terminal 05, and a lead wire I82 connects the terminal 84 with a lead wire I83 attached at one of its ends to the stationary contact element I46 and at its other end to the terminal II3. A lead wire I84 connects the terminal IIZ with the lead wire I19. And a lead wire I85 connects the movable and resilient contact element I41 with the side of the secondary of the transformer opposite the side to which the lead wire I12 is attached.

The manner in which the oil burner control operates will now be described. In Fig. 10 all of the parts of the apparatus are disclosed in position as when the oil burner is extinguished and the temperature of the space to be heated is the desired temperature. When the temperature of said space to be heated falls below said desired temperature, the movable contact element 26 of the room thermostat engages the stationary con= tact element I15 thereof. The contact elements 61 and 69 being in engagement, a circuit is completed through the resistor 83 immediately upon engagement of the contact elements 20 and I15 with each other, said circuit being traced from the secondary of the transformer through the lead wire I12 to the terminal I10, thence through the lead wire I13 to the bi-metallic strip 26, thence through the stationary contact element I15 and the lead wire I10 to the terminal I1I, thence through the conducting plate 63 to the movable contact element 61, thence through the stationary contact element 69 and the lead wires I18 and MI to the terminal 85, thence through the resistor 83, the terminal 64, and the lead wires I82 and I83 to the stationary contact element I46, and thence through the movable and resilient contact element I41 and the lead wire I05 back to the secondary of the transformer. Energization of the resistor 63 causes its wire strand to be lengthened, as already stated, to allow the coil spring 93 to swing the block or lava 88 upon its axis and cause the contact elements I04, 96 and I09, I05 and I16, I06, respectively, to come into engagement. Thus a holding circuit through the resistor 83 is established, said holding circuit being traced from the secondary of the transformer 49 through the lead wire I12 to the terminal I10, thence through the lead wire I 13 to the element 20, thence through the element I15 and the lead wire I14 to the terminal I1I, thence through the conducting plate 63 to the movable contact element 66, thence through the stationary contact element 68 engaged with said element 66, thence through the lead wire I11 to the screw contact I06, thence through the spring clip I I0 to the lead wire I8I, thence through the terminal 85, the re- Sistor 83 and the terminal 84 to the lead wire I82, and thence through the lead wire I83, the contact elements I46 and I41 and the lead wire I85 back to the secondary of the transformer. It will be apparent that the holding circuit just described will remain made until later broken at the contact elements 66 and 68. Also, when the resistor 83 is energized to cause the contact elements I04 and 96 to engage each other, a circuit is completed through the ignition device I5, said circuit being traced from the line wire I58 through the terminal I51 and the stationary contact plate 91 to the contactor I03 of the contact element 99, thence through the contactor I04 to the contact strip 96, thence through the terminal I66 and the lead wire I65 to the ignition device I5, and thence through the lead wire I64 and the terminal I60 to the line wire I6I. The circuit through said ignition device I5 will remain made so long as the resistor 83 is energized. And when the resistor 63 is energized to cause the contact elements I09 and I05 to engage each other, a circuit is completed through the resistor I I I, said circuit being traced from the secondary of the transformer 49 through the lead wire I12 to the terminal I10, thence through the lead wire I13 to the element 20, thence through the element I15 and the lead wire I14 to the terminal I1 I, thence through the conducting plate 63 and the lead wire I16 to the screw contact I05, thence through the spring clip I09 and the lead wire I19 to the lead wire I84, thence through the terminal II2, the resistor III and the terminal II3 to the lead wire I83, and thence through the contact elements I46 and I41 and the lead wire I85 back to the secondary of the transformer. Thus the resistor III when once energized will obviously remain energized at least until the contact elements 66 and 68 are separated to break the holding circuit for the resistor 83. Energization of the resistor III causes its wire strand to be lengthened, as already stated, to allow the coil spring I2I to swing the block or lava II6 upon its axis and cause the contact elements I29, 91 and I32, I30, respectively, to come into engagement. When the contact elements I29 and 91 engage each other, a circuit is completed through the motor I6, as well as through the control valve I1, said circuit being traced from the line wire I58 through the terminal I51 and the stationary contact plate 91 to the contactor I29 of the contact element I24, thence through the contactor I28 and the stationary contact strip I22 to the terminal I68, thence through the lead wire I61 to the motor I6 and through the lead wire I69 to the control valve I1, and thence through the lead wire I64-and the terminal I60 to the line wire I6I.

It will now be evident that upon engagement of the contact elements 20 and I15 of the room thermostat, the ignition device I5, the motor I6 and the control valve I1 will each be energized and thus set in operation to perform its ordinary service. For some reason or other, the ignition device I5 may fail to properly function. That is, said ignition device may fail to ignite the fuel fed to the burner by the motor I6 through an orifice which may be controlled by a valve such as I1, or the fuel feed may fail. In the event of no combustion occurring in the burner due to failure of ignition, the contact elements 66 and 68, controlling the holding circuit for the resistor 83 as already stated, will remain in engagement due to the fact that said contact elements 66 and 68 are caused to be separated only by a rise in temperature in the stack I9. Eventually then, because of energization of the resistor 83 for an undue length of time, the lei-metallic strip I35 will absorb sufficient heat from said resistor 83 to separate the contact elements I46 and I41 in the manner as already explained. Thus both of the resistors 83 and III will be de-energized, and the apparatus will be rendered inoperative and can be reset only by manually depressing the button I56 as before mentioned. When said ignition device functions to cause combustion to occur in the burner, the stack I9, naturally, immediately commences to heat up, and the thermostatic element 35 simultaneously contracts to move the rod 4| inwardly of the stack. The U-clip 59 with its extension portion 82 moves inwardly with said rod, and said extension portion 82 engages the movable switch element 13 to cause the conducting boss 14 thereon to engage the conducting boss 15 upon the movable switch element 66. A holding circuit is thus made through the resistor I I I, to be effective in keeping said resistor I I I energized when the resistor 83 is de-energized (to break the switch I09, I05 in the circuit before made through the resistor III) by later separation of the contact elements 66 and 68 in the holding circuit for said resistor 83. contact elements 66 and 68 are separated, as hereinbefore set forth, by further inward movement of the rod 4I, through the instrumentality of the extension portion 82 pushing against the switch element 13 which in turn pushes by its boss 14 against the boss 15 upon the switch element 66. Obviously, de-energization of the resistor 83 separates the contact elements I04 and 96 and breaks the ignition device circuit to render the ignition device inoperative. tioned, as soon as the rod 4I starts to move inwardly, the extension portion 19 upon the U-clip 58 releases the movable switch element 61 and this springs away from the stationary switch element 69, so that the circuit through the resistor 83 including the elements 61 and 69 is broken just after the holding circuit through said resistor 63 including the elements 66 and 68 is made by engagement of the elements H0 and I06.

The holding circuit through the resistor III, which is made by engagement of the bosses I4 and 15 with each other while the contact elements 66 and 68 are engaged, is traced from the secondary of the transformer 49 through the lead wire I12 to the terminal I10, thence through the lead wire I13 and the element 20 to the element I15, thence through the lead wire I14, the terminal Ill and the conducting plate 63 to the switch element 66, thence through the bosses 15 and 14 to the switch element 13, thence through the lead wire I and the screw contact I30 to the spring clip I32, thence through the lead wires I19 and I84 to the terminal II2, thence through the resistor III and the terminal I I3 to the lead wire I83, and thence through the contact elements I46 and I41 and the lead wire I85 back to the secondary of the transformer. It will be evident that the resistor III will, when energized by the engagement of the bosses or contacts 14 and 15, remain energized until the contact elements 20 and I15 are disengaged.

When the oil burner furnace has caused the space having the room thermostat to reach the desired and predetermined temperature, the contact elements 20 and I15 become disengaged, and thus the circuit through the resistor I I I is broken. As a consequence, the contact elements I29, 91 and I32, I30 are separated by contraction of the wire strand of said resistor III. Separation of said contact elements I29 and 91 obviously breaks Said As before men- 1 the circuit through the motor I6 and the control valve I1, and said motor becomes inoperative and said valve shuts off. Thus the oil burner is extinguished and the stack starts to cool down. Upon inward movement of the rod M, the U-clip 58 with extension portion I9 was arrested by the stop member I6. When the oil burner is extinguished, said rod 4| commences to move outwardly as already described. During the outward movement of the rod 4|, the extension portion I9 engages the contact element 61 and causes this to engage the contact element 69, while the ex tension portion 82 releases the switch elements 66 and I3 and engages the stop member 80. Upon being released by said extension portion 82, the switch element 66 first engages the switch element 68, and the boss I4 upon the switch element I3 later becomes removed from the boss 15 upon the switch element 66. Thus the parts of the apparatus are returned to their normal positions, as shown in Fig. 10, ready to again operate in the manner as explained when the room thermostat again closes as the space to be heated calls for heat.

In Figs. 1, 3, 4, and 5, numeral I86 represents an insulating plate which separates the terminals I68, I51, I60 and I66, having connection with the line wires I58 and I6I, from the remainder of the parts in the casing 25. Said insulating plate I86 is supported, as at I81, by an offset portion I88 of the stationary contact plate 91.

Attention is called to the fact that the contactors I28, I29 and I03, I04 of the contact elements I24 and 99, respectively, and the plate 97 and the strips 96 and I22 which said contact elements engage, are all adapted to be conductively connected in circuits including the line wires I58 and I6I. Thus there may at times be a tendency for the elements I29, 91 and I04, 96, respectively, to stick together, due to a certain amount of arcing at said elements caused by the current of relatively high voltage from the line wires. In case there is such tendency toward sticking together of said elements I29, 91 and I04, 96 when the insulating blocks H6 and 86 swing in direction away from the insulating panel 50, the contactors I28 and I03 of the contact elements I24 and 99, respectively, will, obviously, be easily and readily removed from the strip I22 and the plate 97, to positively break the corresponding circuits, and a rocking action will as a result of the removal of said contactors I28 and I03 be imparted to said contact elements I24 and 99, which rocking action will cause the contactors I29 and I89 to have a rocking or rolling action tending to remove said contactors from the plate 91 and the strip 96, rather than a direct lifting movement as would be the case were the special type of contact elements I24 and 99 as illustrated and described not employed.

Desirably, a permanent magnet I89 is situated adjacent to the movable contact element 20 of the room thermostat. The function of said magnet I89 is to firmly hold the contact elements 20 and I15 in engagement when once together, and thus provide a regulatable differential for the smooth and proper operation of the oil burner control. That is to say, were the permanent magnet I89, or equivalent, not employed, there would be tendency for the elements 20 and M5 to separate too quickly upon elevation of the temperature of the space being heated. Also, said magnet I89 evidently provides for a quick and snappy make and break of the switch of the room thermostat.

The thermal electric switches 2| and 22 and the safety electric switch 24 are adapted to be connected in circuits of relatively low voltage, in-

cluding the stepped-down secondary of the transformer 49. The employment of thermal electric switches, such as 2I and 22, which are directly responsive in their operation to expanding and contracting actions of resistors, such as 83 and III, which resistors expand and contract immediately upon receiving fiow of relatively light current, makes provision for eflicient and effectual operation of the various electric switches manipulated by the thermal electric switches 2I and 22 practically instantaneously with the opening and closing of the circuits controlling said thermal electric switches. Inasmuch as the resistors 83 and III are non-inductive, the room thermostat and the other electric switches of the oil burner control in circuit with the secondary of the transformer can incorporate very delicate and fine electrical contacts. In practice, the opperating power required by the resistors 83 and III does not have to exceed a very few watts, which, flowing through a non-inductive circuit, causes practically no arcing at the room thermostat contacts, or at the other contacts in circuits including the secondary of the transformer.

The oil burner control of the invention will evidently function to care for each and all of the heating problems which may present themselves. Upon failure of ignition, the safety electric switch will be surely and positively operated to render the ignition device and the fuel forcing motor inoperative and to break the circuit through the means operating the control valve, thus insuring that said valve will automatically close. Upon the flame becoming extinguished for any reason before the space being heated is satisfied to break the circuit at 20 and I15, the parts of the oil burner control will all automatically return to normal positions as in Fig. 10, and immediately the resistors 83 and III will be energized, as already set forth, to thereafter cause either proper ignition and combustion to occur, provided the trouble was temporary, or the safety switch to be broken, provided the trouble is not temporary and some adjustment of the fuel feed or other part of the oil burner proper is required.

The novel and improved oil burner control includes an ordinary room thermostat consisting of a single bi-metallic strip or blade, which necessitates the employment of only a quite simple wiring system or arrangement as illustrated and described.

What is claimed is:

1. A control system, for a burner having electrically actuated fuel feeding and ignition means, comprising a main control switch, a combustion responsive switching mechanism having first and second contacts which are closed in the absence of combustion and are successively opened upon the establishment of combustion, and third contacts which are open in the absence of combustion and closed upon the establishment of combustion prior to the opening of .the second contacts, a first multiple contact relay operable when energized to close the circuit of the fuel feeding means and a holding circuit through its actuating means including said third contacts, a circuit for energizing the first relay actuating means, a second multiple contact relay including an actuating means operable when energized in response to the closing of the main control switch and said first contacts to successively close the circuit of the ignition means and the circuit for energizing the first relay actuating means, and a circuit including the second relay actuating means and said second contacts for maintaining energization of said second relay actuating means until said third contacts are closed.

2. A control system, for a burner having electrically actuated fuel feeding and ignition means, comprising a main control switch, a combustion responsive switching mechanism having first and second contacts which are closed in the absence of combustion and are successively opened upon the establishment of combustion, and third contacts which are open in the absence of combustion and are closed upon the establishment of combustion prior to the opening of the second contacts, a first multiple contact relay operable when energized to close the circuit of the fuel feeding means and a holding circuit through its actuating means including said third contacts, a circuit for energizing the first relay actuating means, a second multiple contact relay including an actuating means constituted as a thermal device operable when energized in response to the closing of the main control switch and said first contacts to successively close the circuit of the ignition means and the circuit for energizing the first relay actuating means, a circuit including the second relay actuating means and said second contacts for maintaining energization of said second relay thermal device actuating means until said third contacts are closed, and a thermostatic safety switch responsive in its operation to the absorption of heat from said thermal device actuating means controlling energization of said thermal device.

3. A control system, for a burner having electrically actuated fuel feeding and ignition means, comprising a main control switch, a combustion responsive switching mechanism having first and second contacts which are closed in the absence of combustion and are successively opened upon the establishment of combustion, and third contacts which are open in the absence of combustion and are closed upon the establishment of combustion prior to the opening ofthe second contacts, a first multiple contact relay operable when energized to close the circuit of the fuel feeding means and a holding circuit through its actuating means inchding said third contacts, a circuit for energizing the first relay actuating means, a second multiple contact relay including an actuating means operable when energized in response to the closing of the main control switch and said first contacts to successively close the circuit of the ignition means and the circuit for energizing the first relay actuating means, and a thermostatic safety switch, controlling energization of the system and rendered operative to open by a prolonged absorption of heat from the actuating means for said second relay.

EVERETT H. WHITE. 

